WPF .NET Framework → .NET Migration

1. Migration Checklist

1.1 Pre-Migration

• Verify .NET Framework version (4.6.1+ recommended)

• Check NuGet package .NET compatibility

• Verify third-party library .NET versions

• Check Windows Forms interop usage

• Check WCF client usage

• Check ClickOnce deployment usage

1.2 Migration

• Convert project file to SDK style

• NuGet packages.config → PackageReference

• Clean up AssemblyInfo.cs

• app.config → appsettings.json (optional)

• Build and fix errors

• Run tests

1.3 Post-Migration

• Test self-contained deployment

• Test single-file deployment

• Ready to Run (R2R) optimization

• Performance benchmark

2. Project File Conversion

2.1 Old Format (.NET Framework)

<?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <Import Project="$(MSBuildExtensionsPath)$(MSBuildToolsVersion)\Microsoft.Common.props" /> <PropertyGroup> <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration> <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform> <ProjectGuid>{GUID}</ProjectGuid> <OutputType>WinExe</OutputType> <RootNamespace>MyApp</RootNamespace> <AssemblyName>MyApp</AssemblyName> <TargetFrameworkVersion>v4.8</TargetFrameworkVersion> <!-- ... hundreds of lines ... --> </PropertyGroup> <!-- ... --> </Project>

2.2 New SDK Format (.NET 10)

<Project Sdk="Microsoft.NET.Sdk">

<PropertyGroup> <OutputType>WinExe</OutputType> <TargetFramework>net10.0-windows</TargetFramework> <Nullable>enable</Nullable> <ImplicitUsings>enable</ImplicitUsings> <UseWPF>true</UseWPF> </PropertyGroup>

<ItemGroup> <PackageReference Include="CommunityToolkit.Mvvm" Version="8.3.*" /> </ItemGroup>

</Project>

3. Step-by-Step Migration

3.1 Try-Convert Tool (Automated)

Install

dotnet tool install -g try-convert

Run

try-convert -p MyApp.csproj

3.2 Manual Conversion

Step 1: Create new project file

<Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <OutputType>WinExe</OutputType> <TargetFramework>net10.0-windows</TargetFramework> <UseWPF>true</UseWPF> <RootNamespace>MyApp</RootNamespace> <AssemblyName>MyApp</AssemblyName> </PropertyGroup> </Project>

Step 2: Migrate NuGet references

<!-- packages.config → PackageReference --> <ItemGroup> <PackageReference Include="Newtonsoft.Json" Version="13.0.3" /> <PackageReference Include="CommunityToolkit.Mvvm" Version="8.3.2" /> </ItemGroup>

Step 3: Clean up AssemblyInfo.cs

SDK style auto-generates most attributes. Keep only custom attributes:

// Properties/AssemblyInfo.cs (keep only necessary items) using System.Runtime.InteropServices;

[assembly: ComVisible(false)] [assembly: Guid("your-guid-here")]

Disable generation in project file (if needed):

<PropertyGroup> <GenerateAssemblyInfo>false</GenerateAssemblyInfo> </PropertyGroup>

4. Breaking Changes

4.1 Removed APIs

API .NET Framework .NET Alternative

BinaryFormatter

✅ ⚠️ Removed for security. Use System.Text.Json

AppDomain.CreateDomain

✅ ❌ Not supported

Remoting

✅ ❌ Use gRPC, SignalR

Code Access Security

✅ ❌ Removed

4.2 WCF Client

<!-- WCF client (server not supported) --> <ItemGroup> <PackageReference Include="System.ServiceModel.Http" Version="8.0." /> <PackageReference Include="System.ServiceModel.Primitives" Version="8.0." /> </ItemGroup>

4.3 Windows Forms Interop

<PropertyGroup> <UseWPF>true</UseWPF> <UseWindowsForms>true</UseWindowsForms> </PropertyGroup>

5. Dual Targeting (Gradual Migration)

5.1 Multi-Target

<PropertyGroup> <TargetFrameworks>net48;net10.0-windows</TargetFrameworks> <UseWPF>true</UseWPF> </PropertyGroup>

<ItemGroup Condition="'$(TargetFramework)' == 'net48'"> <Reference Include="System.Windows.Forms" /> </ItemGroup>

<ItemGroup Condition="'$(TargetFramework)' == 'net10.0-windows'"> <PackageReference Include="Microsoft.Windows.Compatibility" Version="9.0.*" /> </ItemGroup>

5.2 Conditional Compilation

#if NET48 // .NET Framework specific code System.Configuration.ConfigurationManager.AppSettings["Key"]; #else // .NET specific code Microsoft.Extensions.Configuration.IConfiguration config; #endif

6. Modern .NET Features

6.1 Nullable Reference Types

<PropertyGroup> <Nullable>enable</Nullable> </PropertyGroup>

public partial class MainViewModel : ObservableObject { [ObservableProperty] private string? _optionalValue; [ObservableProperty] private string _requiredValue = string.Empty; }

6.2 File-Scoped Namespaces

// Old namespace MyApp.ViewModels { public class MainViewModel { } }

// New namespace MyApp.ViewModels;

public class MainViewModel { }

6.3 Global Usings

// GlobalUsings.cs global using System; global using System.Collections.Generic; global using System.Collections.ObjectModel; global using System.Linq; global using System.Threading.Tasks; global using CommunityToolkit.Mvvm.ComponentModel; global using CommunityToolkit.Mvvm.Input;

7. Deployment

7.1 Self-Contained

dotnet publish -c Release -r win-x64 --self-contained true

7.2 Single File

<PropertyGroup> <PublishSingleFile>true</PublishSingleFile> <SelfContained>true</SelfContained> <RuntimeIdentifier>win-x64</RuntimeIdentifier> <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract> </PropertyGroup>

7.3 Ready to Run (AOT)

<PropertyGroup> <PublishReadyToRun>true</PublishReadyToRun> </PropertyGroup>

8. Common Issues

Issue Solution

System.Drawing error Add System.Drawing.Common NuGet

WCF server code Migrate to CoreWCF or gRPC

app.config reading Use Microsoft.Extensions.Configuration

XAML designer error Requires Visual Studio 2022 17.8+

ClickOnce Replace with MSIX or custom updater

9. Resources

• .NET Upgrade Assistant

• Porting from .NET Framework

• WPF Migration Guide

• Breaking Changes in .NET